Mon, 13th Sep 2021

Tight Conditions on the Irish Power System

Multiple Amber Alerts issued – September 2021

The last week has seen challenging conditions on the Irish electricity grid, with three Amber Alerts issued by EirGrid. These alerts indicate that the power grid is in a vulnerable condition with limited capability to handle any additional contingency event such as the unexpected failure of a large power station.

The presence of three Amber Alerts in a single week, out of a total of seven issued during 2021 so far, highlights the severity of the situation. VIOTAS Market Operations Analyst Ayodele Bickersteth, takes us through some of the reasons behind this situation and what the forecast looks like for the coming winter.

Demand Side Units dispatched to provide support

Demand Side Units (DSU), made up of large energy consumers that are willing to adjust their power consumption from the grid over certain periods, were called upon on multiple occasions to help stabilise the power system and reduce system stress.

VIOTAS thanks all our customers who participated in these dispatches, making a significant contribution to the electricity grid. Your participation in VIOTAS #DemandResponse is contributing to Ireland’s #LowCarbon future and protecting the stability of the grid.

Contributing factors

This situation has been caused by a confluence of factors, particularly driven by planned or forced maintenance outages on a number of large power stations, and unusual weather conditions leading to very low output from wind generation.

Weather conditions

Wind generation plays a huge role on the Irish electricity grid, and already produces in excess of 40% of Ireland’s total electricity consumption over the course of the year. However, periods with low wind speeds have the potential to leave the system at risk.

During the evening peak period on three weekdays last week, total all-island wind generation was less than 400 MW, equating to less than 9% of the maximum wind output which is approaching 4,500 MW. Low wind output during high demand weekday evening peak periods, especially when these coincide with outage periods on one or more large power stations, represent some of the most challenging conditions on the grid.

Impact on electricity prices

Market conditions caused the imbalance settlement price to exceed €1,000 /MWh on three days last week, hitting an all-time high of €4,680 /MWh on Thursday 9th September – which is more than 50x the average price level over the preceding 12-month period.  Such high prices indicate the high degree of scarcity on the system.

Implications for winter

Experiencing such tight conditions, and the associated Amber Alerts, during relatively mild conditions during September warns of potentially challenging conditions over the coming winter period. Winter peak power demands are regularly more than 1,000 MW in excess of those seen during the last week.

All eyes remain on the two large power stations currently experiencing long duration maintenance outages. If these plants return to service as currently expected during October and November respectively, this will significantly improve the situation.